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Section 2
Chapter
8
Adult Elective Orthopaedics and Spine
Knee III Structured SBA
Kiran Singisetti
KNEE III STRUCTURED SBA QUESTIONS
1. A 65-year-old man presents to the clinic after
initial improvement of knee pain with a knee
arthroplasty performed 18 months previously.
He now reports recent onset of patellar crepitus
and jumping of the patella. Radiographs show no
change in position of the posterior stabilised
knee replacement with patella resurfacing.
This presentation could be related to which of
the following conditions?
A. Hypertrophic scar tissue at the inferior pole
of the patella impinging on the femoral component during extension
B. Hypertrophic scar tissue at the inferior pole
of the patella impinging on the femoral component during flexion
C. Hypertrophic scar tissue at the superior pole
of the patella impinging on the femoral component during extension
D. Hypertrophic scar tissue at the superior pole
of the patella impinging on the femoral component during flexion
E. Patellar component loosening
2. During a cruciate retaining knee arthroplasty,
the femoral size sagittal measurement comes up
in between sizes 4 and 5.
Which of the following statements is correct?
A. If you are using anterior referencing, a size 5
femoral component may cause flexion
instability
B. If you are using posterior referencing, a size 5
femoral component may cause flexion
instability
C. If you are using anterior referencing, a size 4
femoral component may cause femoral notching
D. If you are using posterior referencing, a size 4
femoral component may cause femoral notching
E. If you are using anterior referencing, a size 5
femoral component may cause tightness of
patellofemoral joint
3. Component alignment and balancing form a key
step in total knee arthroplasty.
Which of the following is a correct guide to
optimise tibial component rotation?
A. Junction of the lateral and medial two-thirds
of the tibial tubercle
B. Achieving optimal posterior medial and
anterior lateral cortical contact
C. Extra-medullary alignment rod overlaying
the lateral–middle third junctions of the tibial
tubercle, the cen tre of the ankle mortise and
second ray of a neutrally aligned foot
D. Minimal anterior lateral tibial plateau
uncoverage
E. Trial reduction with absolute congruence of
the femoral component and the anterior edge
of PE tibial bearing surface
4. A patient attends the arthroplasty knee clinic 2
years following right total knee replacement. In
the past year, she has complained of a sense of
distrusting the knee without giving way, difficulty with stair descent, recurrent effusions and
anterior knee pain.
Possible causes for her symptoms could include
which of the following?
A. Inadequate restoration of the tibial slope
B. Oversizing of the femoral component
C. Over-resection of the distal femur
D. Too little posterior femoral condylar
resection
E. Use of an anterior referencing knee system
5. A 27-year-old female felt a pop during a tackle
while playing football.
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Knee III Structured SBA
Which of the following ligament component
deficiency causes a positive Pivot shift test?
A. Anterolateral bundle of ACL
B. Anteromedial bundle of ACL
C. Posterolateral bundle of ACL
D. Posteromedial bundle of ACL
E. Posteromedial bundle of PCL
6. A patient with a previous ORIF of a lateral tibial
plateau is seen in clinic and listed for a total knee
replacement.
Regarding the surgical approach for knee
replacement, which of the following statements
is correct?
A. Avoid previous incision scars
B. Dissect superficial to the deep fascia
C. If longitudinal scars exist, choose the medial-
most incision that affords appropriate exposure
D. Respect the lateral-based vascular anatomy of
the skin
E. Transverse scars may be crossed with an inci-
sion in a perpendicular manner
7. A 70-year-old woman with tricompartmental
knee osteoarthritis is scheduled to have a total
knee replacement.
Which of the following intraoperative steps is
not useful in improving patellofemoral
tracking during total knee arthroplasty?
A. External rotation of the femoral component
B. External rotation of the tibial component
C. Joint line preservation
D. Lateralisation of the femoral component
E. Lateralisation of the patellar component
8. A 56-year-old woman presents with a spontan-
eous onset of pain in the medial aspect of knee
joint.
Which of the following is a false statement
regarding spontaneous osteonecrosis of the
knee (SONK)?
A. Bone scan has a low specificity and sensitivity
in diagnosis of the condition
B. Core decompression is a useful treatment
following subchondral collapse
C. Mainstay of initial treatment is non-operative
D. It is more common in females
E. MRI is useful in early diagnosis of the
condition
9. A retired manual labourer presents with gradual
worsening of knee pain with a previous history
of high tibial osteotomy (HTO) performed 15
years earlier (Figure 8.1). Radiographs show progressive arthritis of the knee joint and you counsel patient about a total knee arthroplasty (TKA).
Which of the following is a likely issue that you
may encounter during TKA following previous
HTO?
A. Bipartite patella
B. Lateral patella instability
C. Patella baja
D. Patella fracture
E. Patella osteonecrosis
(a) (b)
Figures 8.1a and 8.1b
(a) Anteroposterior (AP) and (b) lateral
radiographs knee
155
Kiran Singisetti
(a) (b)
Figures 8.2a and 8.2b
(a) Anteroposterior (AP) and (b) lateral
radiographs right knees
10. A patient with medial compartment knee arthritis
attends your clinic. He is keen to consider a medial
(partial) unicompartmental arthroplasty on the
right knee. His radiographs are shown in Figure 8.2.
Which of the following is not a contraindication for this procedure?
A. ACL deficiency
B. Anterior knee pain
C. Fixed flexion deformity
D. Inflammatory arthritis
E. Uncorrectable varus deformity of more
than 15°
11. Which of the following statements is false
regarding the surgical approach for primary
total arthroplasty in a 62-year-old patient with
knee arthritis?
A. Lateral parapatellar approach is useful in
fixed valgus deformity of knee
B. Midvastus approach is relatively contraindi-
cated in obese patients
C. Midvastus approach may potentially achieve
earlier rehabilitation
D. Minimally invasive surgical (MIS) approach
has no long-term functional advantage
E. Subvastus approach is an extensile approach
12. Your colleague encourages you to use a knee
replacement prosthesis that has the option of
using an ‘all-polyethylene tibia component’.It
would be prudent to look at the cost, advantage
and disadvantages of the implant before considering a change of practice.
Which of the following is false regarding an
‘all-polyethylene tibia component’?
A. Better functional outcome
B. Better stability
C. Less modularity
D. Less osteolysis
E. More expensive
13. A patient reports continuing instability followi ng
a previous single bundle ACL reconstruction
using hamstring graft. MRI suggests intact graft.
Which of the following statements is correct
regarding tunnel malposition?
A. Too anterior femoral tunnel limits flexion of
knee
B. Too anterior femoral tunnel causes rotational
instability
C. Too anterior tibial tunnel limits flexion of
knee
D. Vertical femoral tunnel can risk femoral
tunnel blowout
E. Vertical inclination of femoral tunnel is asso-
ciated with rotational instability
14. A 20-year-old elite football player sustains an
anterior cruciate ligament (ACL) rupture and
reports instability symptoms despite a focused
exercise plan. He attends a specialist knee clinic.
He wants to know the best graft option for a
potential ACL reconstruction that would allow
early return to sports.
Which of the following graft options would you
consider in this situation?
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Knee III Structured SBA
A. Bone–patella–tendon–bone autograft
B. Hamstring (four strand) autograft
C. Quadriceps tendon autograft
D. Synthetic graft
E. Tendo-Achilles allograft
15. While performing a total knee arthroplasty, you
are faced with a situation of normal extension
gap but tight flexion gap.
Which of the following solutions can be useful
in this situation for sagittal balancing of the
knee?
A. Cut more proximal tibia
B. Decrease the size of the femoral component
C. Use distal femoral augmentation
D. Use a thicker polyethylene insert
E. Use a thinner polyethylene insert
16. A 24-year-old male walks into your clinic with a
varus thrust at the right knee. He reports right
knee pain and instability symptoms following a
motorbike accident sustained 3 weeks ago. Dial
test reveals increased external rotation of the right
foot at 30° flexion but not at 90° flexion of knee.
Which of the following is the most likely ligament injury?
A. Isolated ACL injury
B. Isolated MCL injury
C. Isolated posterolateral corner injury
D. Isolated PCL injury
E. Posterolateral corner and PCL injury
17. A 22-year-old female office worker had a previ-
ous arthroscopic total medial meniscectomy at a
different hospital.
Which of the following situations is not a contraindication for meniscal transplantation?
A. Asymptomatic meniscal loss
B. Chondral changes
C. Inflammatory arthropathy
D. Instability
E. Malalignment
18. A 21-year-old woman presents with recurrent
instability of patella following an injury sustained 3 years ago.
How is the isometric point for the femoral
tunnel referenced from adductor tubercle when
considering a medial patellofemoral ligament
(MPFL) reconstruction?
A. At the adductor tubercle
B. Distal and anterior to the adductor tubercle
C. Distal and posterior to the adductor tubercle
D. Proximal and anterior to the adductor
tubercle
E. Proximal and posterior to the adductor
tubercle
19. A 60-year-old male presents at the ED with a
sudden onset of knee pain following a twisting
incident at home. He underwent a medial unicompartmental knee replacement 5 years ago.
His radiographs are shown in Figure 8.3.
(a) (b)
Figures 8.3a and 8.3b
(a) Anteroposterior (AP) and (b) lateral
radiographs left knee
157
Kiran Singisetti
Which of the following is a true statement
regarding liner dislocation with unicompartmental knee arthroplasty?
A. Closed reduction of liner dislocation is usu-
ally successful
B. Early liner dislocation can be due to
impingement
C. Fixed bearing has a higher risk of liner dis-
location compared with mobile bearing
D. Lateral unicompartmental knee replacement
has less risk of liner dislocation compared
with medial unicompartmental knee
E. Residual cement debris is a common problem
with newer uncemented prosthesis design
20. A 30-year-old presents with mechanical knee
symptoms following an injury 3 months ago.
MRI shows a medial meniscus tear involving
the middle third.
Which of the following meniscal tear patterns
has the worst prognosis for meniscal repair?
A. Bucket handle
B. Horizontal
C. Longitudinal
D. Parrot beak
E. Radial tear
21. A 20-year-old footballer presents with an unstable
tear of the medial meniscus involving the body
and anterior horn. You decide to repair the
meniscus tear due its location in the red-red zone
but find it difficult to access the anterior horn.
Which of the following arthroscopic meniscal
repair techniques is useful for repair of an
anterior horn meniscal tear?
A. All-inside
B. All-outside
C. Inside-out
D. Outside-in
E. Transtibial pull-out suture
22. A 13-year-old girl presents with a spontaneous
onset of knee pain and mechanical symptoms in
the last 6 months. MRI shows the following
lesion on lateral femoral condyle (Figure 8.4).
Which of the following statements is true
related to this diagnosis?
A. Condition is more common in females
B. Lateral aspect of medial femoral condyle is
the most common location
Figure 8.4
MRI scan knee
C. Skeletally immature patients respond well to
non-operative management
D. This condition is more common in the elbow
compared with the knee joint
E. Unstable lesions can be treated by subchon-
dral drilling
23. A 70-year-old woman with valgus knee arthritis
is being considered for a total knee replacement.
On examination, you find the medial collateral
ligament to be intact.
Which of the following statements is false?
A. A constrained prosthesis is more likely to be
used if there is a fixed valgus deformity
B. It is better to release the iliotibial band in
knees too tight laterally in extension, but
not in flexion
C. Patellar instability is a common problem with
valgus knees
D. Peroneal nerve palsy is more common in
valgus knee compared with varus knee
deformity correction
E. The posterior condylar axis is more reliable
than the transepicondylar axis for setting the
correct femoral component rotation
24. A 30-year-old amateur footballer attends clinic
following a knee injury sustained a few months
previously. Examination and imaging confirm a
high-grade ACL injury.
While counselling about ACL reconstruction,
which of the following statements is not true
about the benefits of an ACL reconstruction?
A. Better chance for return to sports
B. Better chance of meniscal repair healing, if
associated with ACL reconstruction
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Knee III Structured SBA
C. Reduces instability symptoms of the knee
D. Reduces risk of future knee arthritis
E. Reduces risk of further meniscal injury
25. An 18-year-old gymnast presents with patellar
instability where non-operative management
(VMO exercises) has failed. CT scan of the knee
is obtained to assess cross-sectional anatomy and
measurements before considering a tibial tubercle osteotomy.
Which of the following is a false statement?
A. High Q angle can cause patellofemoral joint
pain
B. Lateral patellofemoral angle opens laterally
C. Normal range for the Insall–Salvati ratio is
0.8–1.2
D. Sulcus angle of less than 140° may suggest
trochlear dysplasia
E. TT–TG distance of more than 20mm is con-
sidered abnormal
26. A 21-year-old female presents with anterior knee
pain, which has failed non-operative management. Imaging shows increased TT–TG distance
with degeneration of the medial facet of the
patella.
Which of the following tibial tubercle osteotomies is recommended in this situation?
A. Lateral and anterior displacement of tibial
tubercle
B. Lateral and posterior displacement of tibial
tubercle
C. Medial and anterior displacement of tibial
tubercle
D. Medial and distal displacement of tibial
tubercle
E. Medial displacement of tibial tubercle
27. During a revision knee arthroplasty procedure,
assessment of remaining bone stock following
removal of prosthesis shows some distal femoral
bone loss. The surgeon decides to seat a femoral
component on whatever remaining bone is present and implants a thicker polyethylene insert.
At follow-up review, the patient reports anterior
knee pain and flexion instability symptoms.
What is the most likely reason for these
symptoms?
A. Lower joint line with decreased posterior
condylar offset
B. Lower joint line with increased posterior con-
dylar offset
C. Not resurfacing the patella
D. Raised joint line with decreased posterior
condylar offset
E. Raised joint line with increased posterior
condylar offset
28. A 25-year-old male underwent ACL reconstruction using quadrupled hamstring graft 2 weeks
previously. He asks for your advice on postoperative rehabilitation, as the physiotherapist
is currently on leave.
Which of the following exercises should be
avoided in the first 4–6 weeks?
A. Closed chain (e.g. squatting) knee exercises
B. Isometric quadriceps exercises
C. Neuromuscular training
D. Open chain (e.g. seated leg extension) exercises
E. Patella mobilisation
29. A 25-year-old female attends clinic following a
knee injury sustained while playing netball.
Clinical examination reveals excessive anterior
laxity with a soft end point on Lachman’s test.
Which of the following statements is true
regarding ACL reconstruction technique?
A. Anterior knee pain is common with ham-
string compared with BPTB autograft use
B.
Femoral tunnel expansion (windscreen wiper
effect) is common with interference compared with suspensory fixation
C. The femoral tunnel is made before the tibial
tunnel in a transtibial techniqu e
D. There is a higher rate of failure in allograft
compared with autograft use in ACL
reconstruction
E. The outcome of single bundle ACL recon-
struction is better with transtibial compared
to anteromedial technique
30. A 12-year-old boy presents with a full-thickness
ACL tear and instability symptoms. Tanner score
is III. Parents are anxious about the long-term
implications of the child’s AC L injury.
Which of the following statements is true
regarding ACL reconstruction in skeletally
immature patients?
A. There is a high risk of growth disturbance
with transphyseal technique
159
Kiran Singisetti
B. It is better to wait until skeletal maturity
before considering ACL reconstruction
C. Interference screw fixation is preferred in
transphyseal technique
D. Oblique femoral tunnel is preferred in trans-
physeal technique
E. Soft tissue grafts are better for transphyseal
technique
31. A 20-year-old athlete attends clinic after an ACL
reconstruction using hamstring graft 6 weeks
ago. He reports hypersensitivity and numbness
at the hamstring graft harvest site related to
damage of infrapatellar branch of the saphenous
nerve (IPBSN).
Which of the following statements is true
regarding this risk of damage to IPBSN?
A. Horizontal incision is better than oblique
incision for reducing the risk of nerve injury
B. Risk is higher in males
C. Risk is higher in younger age
D. The IPBSN is closer to semitendinosus com-
pared with gracilis tendon
E. Vertical incision has higher risk of injury
compared with oblique incision
32. A 25-year professional basketball player attends
your sports knee clinic to discuss treatment
options for ACL deficient right knee.
Which of the following statements is true when
counselling about graft options for ACL
reconstruction?
BPTB – Bone patella tendon bone graft
HT – Hamstring graft
A. BPTB graft has a low risk of donor site mor-
bidity compared with HT
B. BPTB graft is useful for double bundle ACL
reconstruction
C. BPTB graft requires a longer duration for
integration compared with HT
D. Irradiated allografts have no donor site mor-
bidity but are more likely to fail
E. Quadrupled HT graft has a lower tensile
strength compared with intact native ACL
Which of the following statements is correct
regarding PCL reconstruction technique?
A. Acute ‘killer turn’ of the graft is encountered
in transtibial technique
B. Direct bone-to-bone healing is seen in trans-
tibial technique
C. Single bundle PCL reconstruction is ten-
sioned in extension or 20° of flexion
D. Transtibial technique allows for anatomic place-
ment of the PCL graft at its tibial attachment
E. Open tibial inlay PCL reconstruction results in
the formation of a long oblique tibial tunnel
34. A 40-year-old man sustains a direct blow injury
to his knee (‘dashboard type’) resulting in a painful swollen knee. The knee feels stable on varus
and valgus stress testing with a posterior sag
detected on posterior drawer test.
Which of the following statements is false
regarding non-operative management of isolated PCL injuries?
A. Early rehabilitation and bracing of isolated
PCL injuries can result in a successful return
to sports
B. Hamstring exercises should be avoided in the
early stages
C. Patella mobilisations performed to minimise
quadriceps inhibition
D. Quadriceps strengthening exercises should be
encouraged
E. Range of movement knee exercise in a supine
position in early stages
35. A 35-year-old woman presents with recurrent
effusion of her knee. MRI shows low signal
intensity on both T1 and T2 with a blooming
artefact appearance (Figure 8.5).
Figure 8.5
MRI scan knee
33. A professional footballer sustains a multiligament knee injury. Initial assessment shows
intact distal neurovascular status. You are considering a PCL reconstruction along with dealing
with other ligament injuries.
160
Knee III Structured SBA
Which of the following statements is correct
regarding this condition?
A. Arthroscopic synovectomy gives good clear-
ance in the diffuse form of this condition
B. Blood coagulation test results are usually
deranged
C. Affects males more than females
D. Histology shows haemosiderin stained multi-
nucleated giant cells
E. Local recurrence of this condition is rare
36. A 70-year-old woman presents with worsening
pain related to valgus knee arthritis. A plain radiograph of both knees on standing is shown in
Figure 8.6. She is keen to consider a total knee
arthroplasty as the pain is not well controlled with
analgesics and is interfering with her walking.
Which of the following is not reliable in setting
external rotation of femoral component?
What would be the most appropriate way to
manage the situation?
A. Abandon the procedure and reschedule on a
different day
B. Ask the anaesthetist to give a muscle relaxant
C. Continue with the procedure accepting exces-
sive scuffing of articular cartilage
D. Perform meniscal resection
E. Pie-crusting to release the MCL
38. A 65-year-old patient underwent a total knee
arthroplasty which resulted in excessive femoral
notching (Figure 8.7).
Which of the following is the most likely cause
of this complication?
A. Excessive external rotation of femoral cutting
block
B. Larger size femoral cutting block with anter-
ior referencing
C. Larger size femoral cutting block with poster-
ior referencing
D. Smaller size femoral cutting block with anter-
ior referencing
E. Smaller size femoral cutting block with pos-
terior referencing
Figure 8.6 Anteroposterior (AP) radiograph both knees
A. Computer navigation
B. Proximal tibia cut
C. Posterior condylar axis
D. Transepicondylar axis (lateral to medial
epicondyle)
E. Whiteside line (trochlear AP axis)
37. During a knee arthroscopy you encou nter a dis-
placed bucket handle medial meniscus tear in a
tight medial compartment. You find it difficult
to insert instrumentation for meniscal repair on
the medial side.
39. A 20-year-old gymnast sustains a twisting knee
injury leading to painful mechanical symptoms.
MRI scan suggests an unstable anterior horn
lateral meniscus tear.
Which of the following treatment options
would be the best way forward to manage the
situation?
A. All inside meniscal repair
B. Inside-out meniscal repair
C. Non-operative treatment
D. Outside-in meniscal repair
E. Partial lateral menisectomy
40. You are performing a total knee arthroplasty for
a 70-year-old woman with varus tricompartmental knee arthritis. During knee balancing, you are
faced with a situation of a normal flexion gap but
tight extension gap.
Which of the following solutions can be useful in
this situation for sagittal balancing of the knee?
A. Cut more proximal tibia
B. Decrease the size of the femoral component
C. More distal femoral resection
161
Kiran Singisetti
(a) (b)
Figure 8.7 (a) and (b) Anteroposterior
and lateral radiograph left knee
D. Use a thicker polyethylene insert
E. Use a thinner polyethylene insert
41. What is your preferred initial treatment of an
active 28-year-old man who presents to you with
tenderness at the insertion of the patella tendon
into the patella?
It has been present for 2 years and mainly
comes on with activity and sport.
A. Eccentric exercises
B. Patella tendon orthosis
C. PRP injection
D. Shock wave therapy
E. Steroid injection
42. A 25-year-old man sustained a twisting injury to
his right knee whilst playing tennis. The next day
he no ticed some swelling. Clinical examination
revealed medial joint line tenderness.
Which of the following tests will most likely
suggest his diagnosis?
A. Axial force down the leg with the patient
prone and the knee flexed to 90°
B. Internal rotation and external rotation of the
flexed knee with axial pressure down the leg
C. Opening of the knee joint with a varus force
D. Rotating on a 20° flexed knee whilst weight
bearing on that side
E. Squat and walk
162
KNEE III STRUCTURED SBA ANSWERS
1. Answer C. Hypertrophic scar tissue at the
superior pole of the patella impinging on the
femoral component during extension
Patellar clunk syndrome is related to the formation of a fibrous nodule on the undersurface of
distal quadriceps, just above the patella. This is
usually related to a posterior stabilised total knee
arthroplasty. Treatment is arthroscopic or open
debridement of the fibrous nodule.
Fukunaga K et al. The incidence of the patel-
lar clunk syndrome in a recently designed mobilebearing posteriorly stabilised total knee replacement. J Bone Joint Surg Br. 2009;91:463–468.
Gopinathan P. Patello-femoral clunk syn-
drome – currentconcepts. JOrthop.2014;11:55–57.
2. Answer D. If you are using posterior referen-
cing, a size 4 femoral component may cause
femoral notching
The anterior referencing technique measures the
size of the femur with the starting point from the
anterior femoral cortex. This reduces the risk of
notching of the anterior femoral cortex, but it is
more difficult to control the posterior condylar
offset. This carries the risk of flexion instability if
the femoral component is undersized. With the
posterior referencing technique, the measurement
is referenced from the posterior condyles, the size
of the flexion gap and posterior condylar offset can
be better controlled, but there is a risk of anterior
notching or overstuffing, if it is between sizes.
Posterior referencing is considered generally
more reliable in reducing the risk of flexion
instability. If you are using a posterior referencing system, when faced with a femur in between
sizes, there are some tips you could use if you
decided to go with a smaller size femoral component. First, you could translate the cutting
block 2mm anteriorly using an anti-notch guide.
This may increase the flexion gap by 2mm but is
usually well tolerated in most cases and avoids
the risk of anterior notching. Second, a 3° flexion
of the femoral component may help in reducing
the risk of anterior notching, though theoretically this may cause some loss of extension.
Fokin AA, Heekin RD. Anteri or referencing
versus posterior referencing in total knee arthroplasty. J Knee Surg. 2014;27:303–308.
Knee III Structured SBA
Charette RS, Sheth NP, Boettner F, Scuderi
GR, Melnic CM. Femoral component sizing
during total knee arthroplasty: anterior versus
posterior referencing. J Bone Joint Surg Rev.
2018;6:e4.
3. Answer E. Trial reduction with absolute con-
gruence of the femoral component and the
anterior edge of PE tibial bearing surface
There are multiple checks that need to be performed to make sure the tibial base plate is
appropriately aligned. The base plate needs to
be aligned with the junction of the medial and
middle thirds of the tibial tubercle. This should
be achieved through rotation and not just simply
translation in the coronal plane. Thi s rotation
should create minimal posterior–medial tibial
plateau uncoverage. Additionally, this rotation
should achieve optimal anterior medial and posterior lateral cortical contact in order to optimise
load transfer and reduce the risk of subsidence.
An additional check would be to use an extramedullary alignment rod clipped to the pinned
tibial baseplate. The rod should overlay the
medial–middle third junction of the tibial tubercle, the centre of the ankle mortise and point to
the first or second ray of a neutrally aligned foot.
Prosthetic clues for assessing tibial rotation
include basing this relationship on a properly
placed femoral component and the semicongruous PE bearing surface. With the knee
fully extended, there should be absolute congruency between the femoral component and anterior edge of the semi-co ngruent tibial PE
component. The knee should then be flexed up
to 90° and again the PE tibial bearing should be
absolutely congruent and without edge loading.
4. Answer E. Use of an anterior referencing knee
system
The patient is describing classic symptoms of
flexion instability caused by an increased flexion
gap compared with extension gap. Patients typically present with recurrent effusions, subjective
instability (especially going downstairs), quadriceps weakness and diffuse peri-retinacular pain.
Flexion instability is the result of a flexion
space that is larger than the extension gap. It is
caused by an inability to balance the flexion and
extension space at the time of index arthroplasty
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